Gold color alloys are employed for many applications where aesthetic considerations are significant including dental restorations and jewelry. Moreover, gold alloys and precious metal alloys containing substantial amounts of gold are widely employed in the electrical and electronics fields where resistance to tarnish and inertness to the atmosphere are desired. However, the ever-escalating costs of gold have necessitated a search for alloys which would provide the same aesthetic and tarnish-resistant properties at substantially lower cost.
Unfortunately, although other alloys having similar gold coloration with no, or relatively low, gold content have been formulated, generally such alloys suffer from low tarnish resistance, particularly in a sulfur-containing environment. Moreover, many such alloys do not possess the requisite hardness and other physical properties for many applications where such gold color alloys are desirable.
It is an object of the present invention to provide a novel gold color alloy which exhibits a desirable gold coloration and highly advantageous resistance to tarnish.
Another object is to provide such an alloy which is relatively low in gold content and which exhibits desirable inertness for dental and other applications together with a useful balance of physical properties.
A further object is to provide dental restorations comprising castings of such an alloy, which castings exhibit desirable physical properties and aesthetically pleasing gold coloration and a high resistance to tarnish.